Rename a few Dart files from camelCase to snake_case (#494)

According to the Dart Effective Guidelines, we should use snake_case for
Dart file. [DO name packages, directories, and source files using
lowercase_with_underscores.](https://dart.dev/guides/language/effective-dart/style#do-name-packages-and-file-system-entities-using-lowercase-with-underscores)


Used the following command to check if there are still files with
camelCase:

```sh
find . -name "*.dart" | grep -E '[[:upper:]]' | awk -F/ '{print $NF}'
```

Is helpful for #493 so that labels are assigned correctly.

app/lib/blackboard/blackboard_view.dart

@@ -10,7 +10,7 @@ import 'package:flutter/material.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 import 'package:intl/intl.dart';
 import 'package:sharezone/groups/group_permission.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:sharezone_common/helper_functions.dart';
 import 'package:sharezone_widgets/theme.dart';
 

app/lib/blackboard/blocs/blackboard_dialog_bloc.dart

@@ -13,7 +13,7 @@ import 'package:group_domain_models/group_domain_models.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:sharezone/blackboard/blackboard_item.dart';
 import 'package:sharezone/markdown/markdown_analytics.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone_common/api_errors.dart';
 import 'package:sharezone_common/blackboard_validators.dart';
 import 'package:sharezone_common/helper_functions.dart';

app/lib/blackboard/blocs/blackboard_page_bloc.dart

@@ -13,7 +13,7 @@ import 'package:rxdart/rxdart.dart';
 import 'package:sharezone/blackboard/blackboard_item.dart';
 import 'package:sharezone/blackboard/blackboard_view.dart';
 import 'package:sharezone/util/api/blackboard_api.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 
 class BlackboardPageBloc extends BlocBase {
   final _viewsSubject = BehaviorSubject<List<BlackboardView>>();

app/lib/blackboard/details/blackboard_details_bloc.dart

@@ -9,7 +9,7 @@
 import 'package:bloc_base/bloc_base.dart';
 import 'package:sharezone/blackboard/blackboard_view.dart';
 import 'package:sharezone/util/api/blackboard_api.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 
 class BlackboardDetailsBloc extends BlocBase {
   final BlackboardGateway gateway;

app/lib/blocs/application_bloc.dart

@@ -9,7 +9,7 @@
 import 'package:analytics/analytics.dart';
 import 'package:bloc_base/bloc_base.dart';
 import 'package:shared_preferences/shared_preferences.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone/util/navigation_service.dart';
 import 'package:streaming_shared_preferences/streaming_shared_preferences.dart';
 

app/lib/blocs/homework/homework_card_bloc.dart

@@ -11,7 +11,7 @@ import 'dart:async';
 import 'package:bloc_base/bloc_base.dart';
 import 'package:firebase_hausaufgabenheft_logik/firebase_hausaufgabenheft_logik.dart';
 import 'package:rxdart/subjects.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 
 class HomeworkCardBloc extends BlocBase {
   final SharezoneGateway api;

app/lib/blocs/homework/homework_dialog_bloc.dart

@@ -13,7 +13,7 @@ import 'package:firebase_hausaufgabenheft_logik/firebase_hausaufgabenheft_logik.
 import 'package:group_domain_models/group_domain_models.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:sharezone/markdown/markdown_analytics.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone/util/next_lesson_calculator/next_lesson_calculator.dart';
 import 'package:sharezone_common/helper_functions.dart';
 import 'package:sharezone_common/homework_validators.dart';

app/lib/blocs/homework/homework_page_bloc.dart

@@ -11,7 +11,7 @@ import 'dart:async';
 import 'package:bloc_base/bloc_base.dart';
 import 'package:firebase_hausaufgabenheft_logik/firebase_hausaufgabenheft_logik.dart';
 import 'package:rxdart/subjects.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone_common/api_errors.dart';
 
 class HomeworkToggleDone {

app/lib/blocs/sharezone_bloc_providers.dart

@@ -95,7 +95,7 @@ import 'package:sharezone/timetable/timetable_add/bloc/timetable_add_bloc_factor
 import 'package:sharezone/timetable/timetable_add_event/bloc/timetable_add_event_bloc_dependencies.dart';
 import 'package:sharezone/timetable/timetable_add_event/bloc/timetable_add_event_bloc_factory.dart';
 import 'package:sharezone/timetable/timetable_page/school_class_filter/school_class_filter_analytics.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone/util/cache/key_value_store.dart';
 import 'package:sharezone/util/cache/streaming_key_value_store.dart';
 import 'package:sharezone/util/firebase_auth_token_retreiver_impl.dart';

app/lib/calendrical_events/bloc/calendrical_events_page_bloc.dart

@@ -12,9 +12,9 @@ import 'package:group_domain_models/group_domain_models.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:sharezone/calendrical_events/models/calendrical_event.dart';
 import 'package:sharezone/timetable/src/widgets/events/event_view.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 
 class CalendricalEventsPageBloc extends BlocBase {
   final TimetableGateway timetabelGateway;

app/lib/calendrical_events/bloc/calendrical_events_page_bloc_factory.dart

@@ -7,9 +7,9 @@
 // SPDX-License-Identifier: EUPL-1.2
 
 import 'package:bloc_base/bloc_base.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 
 import 'calendrical_events_page_bloc.dart';
 

app/lib/comments/comment_view_factory.dart

@@ -8,7 +8,7 @@
 
 import 'package:meta/meta.dart';
 import 'package:sharezone/groups/group_permission.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:timeago/timeago.dart' as timeago;
 
 import 'comment.dart';

app/lib/comments/widgets/comment_section_builder.dart

@@ -14,7 +14,7 @@ import 'package:sharezone/comments/comments_bloc.dart';
 import 'package:sharezone/comments/comments_bloc_factory.dart';
 import 'package:sharezone/comments/comments_gateway.dart';
 import 'package:sharezone/comments/widgets/comment_section.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:user/user.dart';
 
 class CommentSectionBuilder extends StatefulWidget {

app/lib/dashboard/bloc/dashboard_bloc.dart

@@ -24,10 +24,10 @@ import 'package:sharezone/timetable/src/models/lesson.dart';
 import 'package:sharezone/timetable/src/models/lesson_data_snapshot.dart';
 import 'package:sharezone/timetable/src/widgets/events/event_view.dart';
 import 'package:sharezone/util/api/blackboard_api.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:sharezone/util/api/homework_api.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 import 'package:sharezone/util/api/user_api.dart';
 import 'package:sharezone_utils/streams.dart';
 import 'package:time/time.dart';

app/lib/dashboard/gateway/dashboard_gateway.dart

@@ -7,10 +7,10 @@
 // SPDX-License-Identifier: EUPL-1.2
 
 import 'package:sharezone/util/api/blackboard_api.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:sharezone/util/api/homework_api.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 import 'package:sharezone/util/api/user_api.dart';
 
 class DashboardGateway {
@@ -21,6 +21,11 @@ class DashboardGateway {
   final SchoolClassGateway schoolClassGateway;
   final UserGateway userGateway;
 
-  DashboardGateway(this.homeworkGateway, this.blackboardGateway,
-      this.timetableGateway, this.courseGateway, this.schoolClassGateway, this.userGateway);
+  DashboardGateway(
+      this.homeworkGateway,
+      this.blackboardGateway,
+      this.timetableGateway,
+      this.courseGateway,
+      this.schoolClassGateway,
+      this.userGateway);
 }

app/lib/dashboard/models/homework_view.dart

@@ -10,7 +10,7 @@ import 'package:firebase_hausaufgabenheft_logik/firebase_hausaufgabenheft_logik.
 import 'package:flutter/material.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 import 'package:intl/intl.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 
 class HomeworkView {
   final String courseName, title;

app/lib/filesharing/dialog/course_tile.dart

@@ -13,7 +13,7 @@ import 'package:sharezone/blocs/application_bloc.dart';
 import 'package:sharezone/groups/group_join/group_join_page.dart';
 import 'package:sharezone/groups/group_permission.dart';
 import 'package:sharezone/groups/src/pages/course/create/course_template_page.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone_widgets/widgets.dart';
 
 class CourseTile extends StatelessWidget {

app/lib/filesharing/rules/filesharing_permissions.dart

@@ -12,7 +12,7 @@ import 'package:flutter/material.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 import 'package:sharezone/blocs/application_bloc.dart';
 import 'package:sharezone/groups/group_permission.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 
 class FileSharingPermissions {
   final SharezoneGateway api;

app/lib/groups/group_join/bloc/group_join_bloc.dart

@@ -14,7 +14,7 @@ import 'package:meta/meta.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:sharezone/groups/group_join/bloc/group_join_function.dart';
 import 'package:sharezone/groups/group_join/models/group_join_result.dart';
-import 'package:sharezone/util/api/connectionsGateway.dart';
+import 'package:sharezone/util/api/connections_gateway.dart';
 
 class GroupJoinBloc extends BlocBase {
   final ConnectionsGateway _connectionsGateway;

app/lib/groups/group_join/bloc/group_join_function.dart

@@ -13,7 +13,7 @@ import 'package:meta/meta.dart';
 import 'package:sharezone/groups/group_join/models/group_join_exception.dart';
 import 'package:sharezone/groups/group_join/models/group_join_result.dart';
 import 'package:sharezone/groups/group_join/models/group_join_result_type.dart';
-import 'package:sharezone/util/api/connectionsGateway.dart';
+import 'package:sharezone/util/api/connections_gateway.dart';
 
 class GroupJoinFunction {
   final ConnectionsGateway _connectionsGateway;

app/lib/groups/src/pages/course/course_details/course_details_bloc.dart

@@ -14,7 +14,7 @@ import 'package:group_domain_models/group_domain_models.dart';
 import 'package:rxdart/subjects.dart';
 import 'package:sharezone/groups/group_permission.dart';
 import 'package:sharezone/groups/src/models/splitted_member_list.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 
 class CourseDetailsBloc extends BlocBase {
   final CourseDetailsBlocGateway _gateway;

app/lib/groups/src/pages/course/course_edit/course_edit_bloc.dart

@@ -12,7 +12,7 @@ import 'package:design/design.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 import 'package:meta/meta.dart';
 import 'package:rxdart/rxdart.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:sharezone_common/api_errors.dart';
 import 'package:sharezone_common/course_validators.dart';
 import 'package:sharezone_common/helper_functions.dart';

app/lib/groups/src/pages/course/course_edit/design/src/bloc/course_edit_design_bloc.dart

@@ -9,7 +9,7 @@
 import 'package:bloc_base/bloc_base.dart';
 import 'package:design/design.dart';
 import 'package:meta/meta.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 
 class CourseEditDesignBloc extends BlocBase {
   final String courseId;

app/lib/groups/src/pages/course/create/src/gateway/course_create_gateway.dart

@@ -9,8 +9,8 @@
 import 'package:app_functions/app_functions.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 
-import 'package:sharezone/util/api/courseGateway.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
 import 'package:sharezone/util/api/user_api.dart';
 import '../bloc/user_input.dart';
 

app/lib/groups/src/pages/school_class/create_course/school_class_create_course_bloc.dart

@@ -15,7 +15,7 @@ import 'package:sharezone/groups/src/pages/course/create/src/analytics/course_cr
 import 'package:sharezone/groups/src/pages/course/create/src/analytics/events/course_create_event.dart';
 import 'package:sharezone/groups/src/pages/course/create/src/bloc/user_input.dart';
 import 'package:sharezone/groups/src/pages/course/create/src/models/course_template.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone/util/string_utils.dart';
 import 'package:sharezone_common/api_errors.dart';
 import 'package:sharezone_common/course_validators.dart';

app/lib/groups/src/pages/school_class/edit/school_class_edit_gateway.dart

@@ -9,7 +9,7 @@
 import 'package:app_functions/app_functions.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 
-import 'package:sharezone/util/api/schoolClassGateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
 
 class SchoolClassEditGateway {
   final SchoolClassGateway _gateway;

app/lib/groups/src/pages/school_class/my_school_class_bloc.dart

@@ -13,7 +13,7 @@ import 'package:group_domain_models/group_domain_models.dart';
 
 import 'package:meta/meta.dart';
 import 'package:sharezone/groups/group_permission.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone_common/helper_functions.dart';
 
 enum SchoolClassDeleteType {

app/lib/main/ist_schon_gruppe_beigetreten.dart

@@ -7,7 +7,7 @@
 // SPDX-License-Identifier: EUPL-1.2
 
 import 'package:common_domain_models/common_domain_models.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 
 Future<bool> istSchonGruppeMitSharecodeBeigetreten(
     SharezoneGateway sharezoneGateway, Sharecode sharecode) async {

app/lib/main/run_app.dart

@@ -23,7 +23,7 @@ import 'package:sharezone/main/flutter_error_handler.dart';
 import 'package:sharezone/main/ist_schon_gruppe_beigetreten.dart';
 import 'package:sharezone/main/plugin_initializations.dart';
 import 'package:sharezone/main/sharezone.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone/util/api/user_api.dart';
 import 'package:sharezone/util/cache/key_value_store.dart';
 import 'package:sharezone/util/flavor.dart';

app/lib/main/sharezone_app.dart

@@ -48,7 +48,7 @@ import 'package:sharezone/pages/settings/timetable_settings/timetable_settings_p
 import 'package:sharezone/pages/settings/web_app.dart';
 import 'package:sharezone/pages/settings_page.dart';
 import 'package:sharezone/timetable/timetable_add/timetable_add_page.dart';
-import 'package:sharezone/util/API.dart';
+import 'package:sharezone/util/api.dart';
 import 'package:sharezone/util/navigation_service.dart';
 import 'package:sharezone_common/references.dart';
 import 'package:showcaseview/showcaseview.dart';

app/lib/notifications/action_requests/show_timetable_event.dart

@@ -12,8 +12,8 @@ import 'package:common_domain_models/common_domain_models.dart';
 import 'package:flutter/material.dart';
 import 'package:notifications/notifications.dart';
 import 'package:sharezone/timetable/timetable_page/timetable_event_details.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 
 ActionRegistration<
     ShowTimetableEventRequest> showTimetableEventRegistrationWith(

app/lib/onboarding/group_onboarding/logic/group_onboarding_bloc.dart

@@ -12,8 +12,8 @@ import 'package:group_domain_models/group_domain_models.dart';
 import 'package:sharezone/dynamic_links/beitrittsversuch.dart';
 import 'package:sharezone/onboarding/group_onboarding/analytics/group_onboarding_analytics.dart';
 import 'package:sharezone/onboarding/group_onboarding/logic/signed_up_bloc.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
 import 'package:sharezone_utils/platform.dart';
 import 'package:user/user.dart';
 

app/lib/pages/homework/homework_details/homework_details_view_factory.dart

@@ -15,7 +15,7 @@ import 'package:meta/meta.dart';
 import 'package:sharezone/filesharing/file_sharing_api.dart';
 import 'package:sharezone/pages/homework/homework_details/homework_details_view.dart';
 import 'package:sharezone/pages/homework/homework_details/submissions/submission_permissions.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:user/user.dart';
 
 import '../homework_permissions.dart';

app/lib/pages/homework/homework_details/submissions/submission_permissions.dart

@@ -9,7 +9,7 @@
 import 'package:firebase_hausaufgabenheft_logik/firebase_hausaufgabenheft_logik.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 
-import 'package:sharezone/util/api/courseGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
 import 'package:user/user.dart';
 
 class SubmissionPermissions {

app/lib/timetable/src/bloc/timetable_bloc.dart

@@ -21,9 +21,9 @@ import 'package:sharezone/timetable/src/models/lesson.dart';
 import 'package:sharezone/timetable/src/models/lesson_data_snapshot.dart';
 import 'package:sharezone/timetable/timetable_page/school_class_filter/school_class_filter_analytics.dart';
 import 'package:sharezone/timetable/timetable_page/school_class_filter/school_class_filter_view.dart';
-import 'package:sharezone/util/api/courseGateway.dart';
-import 'package:sharezone/util/api/schoolClassGateway.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/course_gateway.dart';
+import 'package:sharezone/util/api/school_class_gateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 import 'package:sharezone/util/api/user_api.dart';
 import 'package:time/time.dart';
 import 'package:user/user.dart';

app/lib/timetable/src/bloc/timetable_selection_bloc.dart

@@ -13,7 +13,7 @@ import 'package:group_domain_models/group_domain_models.dart';
 import 'package:quiver/core.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:sharezone/timetable/src/models/lesson.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 import 'package:user/user.dart';
 
 class EmptyPeriodSelection {

app/lib/timetable/timetable_add/bloc/timetable_add_bloc.dart

@@ -16,7 +16,7 @@ import 'package:sharezone/timetable/src/models/lesson.dart';
 import 'package:sharezone/timetable/src/models/lesson_length/lesson_length_cache.dart';
 import 'package:sharezone/timetable/src/models/time_type.dart';
 import 'package:sharezone/timetable/timetable_add/bloc/timetable_add_bloc_dependencies.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 import 'package:sharezone_common/api_errors.dart';
 import 'package:sharezone_common/validators.dart';
 import 'package:time/time.dart';

app/lib/timetable/timetable_add/bloc/timetable_add_bloc_dependencies.dart

@@ -8,7 +8,7 @@
 
 import 'package:meta/meta.dart';
 import 'package:sharezone/timetable/src/models/lesson_length/lesson_length_cache.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 
 class TimetableAddBlocDependencies {
   final TimetableGateway gateway;

app/lib/timetable/timetable_add_event/bloc/timetable_add_event_bloc.dart

@@ -16,7 +16,7 @@ import 'package:sharezone/calendrical_events/models/calendrical_event_types.dart
 import 'package:sharezone/markdown/markdown_analytics.dart';
 import 'package:sharezone/timetable/src/models/lesson_length/lesson_length_cache.dart';
 import 'package:sharezone/timetable/timetable_add_event/bloc/timetable_add_event_bloc_dependencies.dart';
-import 'package:sharezone/util/api/timetableGateway.dart';
+import 'package:sharezone/util/api/timetable_gateway.dart';
 import 'package:sharezone_common/api_errors.dart';
 import 'package:sharezone_common/validators.dart';
 import 'package:time/time.dart';